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| 电子束焊熔池温度场及小孔演变的数值模拟 |
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王佳杰1,2, 矫勇3, 于久灏1, 王国星1, 许建平1
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1.黑龙江工程学院 材料与化学工程学院, 哈尔滨 150050;2.哈尔滨工业大学 先进焊接与连接国家重点实验室, 哈尔滨 150001;3.哈尔滨电机厂有限责任公司, 哈尔滨 150040
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| 摘要: |
| 针对2024铝合金电子束定点焊物理输运特点，在质量守恒、动量守恒、能量守恒以及VOF方程的基础上，建立了电子束深熔焊三维数学模型，系统描述了加热阶段以及冷却回填阶段点焊熔池的温度场以及小孔的演变过程，并通过焊缝形貌对比对计算结果进行了试验验证.结果表明，蒸汽反冲压力是小孔形成和加深的主要驱动力；在小孔出现以后，加热阶段的熔池最高温度区间位于瞬态小孔的底部，而当熔池冷却时冷却速度由上至下逐渐增加，并导致了焊缝微观组织的晶粒细化. |
| 关键词: 电子束定点焊 温度场 小孔 反冲压力 |
| DOI： |
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| 基金项目:黑龙江省自然科学基金资助项目（E201458）；哈尔滨市应用技术研究与开发项目（青年后备人才）（2014RFQXJ015）；黑龙江工程学院博士科研基金资助项目（2015BJ11） |
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| Numerical simulations of temperature field and keyhole evolution for electron beam welding pool |
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WANG Jiajie1,2, JIAO Yong3, YU Jiuhao1, WANG Guoxing1, XU Jianping1
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1.Department of Materials and Chemical Engineering, Heilongjiang Institute of Technology, Harbin 150050, China;2.State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China;3.Harbin Electric Machinery Company Limited, Harbin 150030, China
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| Abstract: |
| In terms of physical transportation characteristics of 2024 aluminium alloy electron beam spot welding, on the basis of conservation equations of mass, momentum, energy and VOF (volume of fluid) equation, a 3D mathematical model for electron beam deep-penetration welding was established. By using this model, the evolutions of temperature field and keyhole for spot welding pool at the heating stage and the cooling backfilling stage were systematically described and validated by weld shape comparison. The results indicate that the vapour-induced recoil pressure is the key driving force for keyhole formation and deepening. As soon as the keyhole appears, the maximum temperature region of welding pool at the heating stage is located at the bottom of the transient keyhole. Meanwhile, the cooling rate of welding pool is increased from the upper to the bottom, which results in the grain refining of weld microstructure. |
| Key words: electron beam spot welding temperature field keyhole recoil pressure |
